P-3 Natops: Ch. 11 Annunciator Lights

Front 1

GEN 2 or GEN 3, GEN 4 or APU GEN OFF light on.

Back 1

Use reset procedure, or place associated BUS MONITORING switch ON. If an engine‐driven generator light remains on steady throughout reset procedures, or goes out momentarily and comes back on, mission should be aborted.
Note: If the APU generator control circuit breaker is out, the APU GEN OFF light will be on. Automatic APU load monitoring above 8,000 feet will be disabled; however, the generator will assume the load.
CAUTION: Generator supervisory panels shall not be exchanged until appropriate maintenance actions are performed.
Note: Ensure GEN 4 AUX CONT and GEN 4 TRANS circuit breakers are set appropriately.

Hint 1

Generator failure, off frequency, over voltage, under voltage, feeder fault, supervisory panel failure, transfer relay 2 or 3 failure, or associated bus monitoring switch OFF.

Front 2

TRANSFORMER RECTIFIER OVERHEAT light ON.

Back 2

Pull respective circuit breaker; No. 3 located at the flight station and No. 1 and 2 located at the main load center.

Hint 2

Transformer Rectifier (TR) overheated.

Front 3

EXTERNAL PWR AVAILABLE light ON (neon), but no power into aircraft.

Back 3

Move EXTERNAL POWER switch to RESET then ON. Check nose gear uplock position. Check battery condition. Check No. 4 runaround feeder circuit breaker. Check external power control circuit breaker.

Hint 3

Wrong phase, nosegear uplock not properly positioned, battery not connected, generator No. 4 runaround feeder circuit breaker out, external power control circuit breaker out.

Front 4

EXTERNAL PWR AVAILABLE light ON partial power into aircraft.

Back 4

Check TR 3 circuit breaker. Check essential DC bus feeder circuit breaker No. 2. Check Monitorable Essential AC ganged circuit breaker in. Check Monitorable Essential bus switch.

Hint 4

Transformer‐rectifier No. 3 ganged circuit breaker out. Essential DC bus feeder circuit breaker No. 2 out. Monitorable Essential AC ganged circuit breaker behind copilot out. Monitorable Essential bus switch off.

Front 5

EXTERNAL POWER light ON.

Back 5

EXTERNAL POWER switch is on.

Hint 5

External power supplying power to aircraft system.

Front 6

No. 1, 2, 3, or 4 PRIMARY FUEL PUMP (parallel) light on during start (between 16 percent and 65 percent rpm).

Back 6

(No action required if it is functioning normally.)

Hint 6

Indicates the secondary fuel pump is functioning properly.

Front 7

No. 1, 2, 3, or 4 PRIMARY FUEL PUMP (parallel) light off during start (between 16 percent and 65 percent rpm).

Back 7

Investigate.

Hint 7

Failure of secondary pump.

Front 8

No. 1, 2, 3, or 4 PRIMARY FUEL PUMP light on, or momentarily ON then OFF, above 65 percent rpm.

Back 8

Pull FUEL SHUTOFF VALVE circuit breaker on Start Essential DC bus.
a. If the light remains on, reset the circuit breaker, and assume the primary pump has failed.
b. If the light goes out, leave the circuit breaker out, and assume a failure of either the 65 percent switch or the speed sense control. If mission is continued, refer to Speed Sense Control Malfunction, paragraph 15.4.

Hint 8

a. Failure of the primary pump.
b. Fuel pumps are in parallel operation possibly due to a speed sense control malfunction.

Front 9

No. 1, 2, 3, and 4 AUTO FEATHER lights are all on.

Back 9

(No action neccesary.)

Hint 9

The automatic feathering circuit has been armed.

Front 10

No. 1, 2, 3, or 4 AUTO FEATHER light on individually.

Back 10

Investigate.

Hint 10

Propeller thrust has dropped to less than 500 pounds of positive thrust; propeller has automatically feathered.

Front 11

No. 1, 2, 3, or 4 engine STARTER CONTROL VALVE OPEN light on.

Back 11

* If light remains on or comes on after start, secure engine by pulling emergency shutdown handle.

Hint 11

Engine starter control valve is open. (Valve should close and light go out when starter button is pulled out at 57 to 64 percent rpm during normal start.)

Front 12

No. 1, 2, 3, or 4 prop feather button light remains on.

Back 12

a. If light remains on following engine shutdown, pull respective propeller feather control circuit breaker (Eng. 2/3 EMDC, 1/4 MEDC), and execute the Emergency Shutdown procedure, paragraph 15.5.1.
b. If light remains on following pressure cutout override, refer to In‐Flight Restart Procedures, paragraph 8.33.1.

Hint 12

Indicates feather pump relay is closed, supplying electrical power to the feather pump.
Possible internal leakage. Incomplete pump cut‐out circuit.

Front 13

FAN OUT light on.

Back 13

Open equipment doors for additional cooling. Use minimum electronic equipment. If EDCs are inoperative (no air‐conditioning available), open AUX vent.

Hint 13

Cabin exhaust fan is inoperative or lack of airflow.

Front 14

EDC TEMP HIGH light on.

Back 14

a. Check engine oil
temperature; if high, correct.
b. If unable to control,
disconnect, monitor for loss
of spread, dump, continue
operation.
CAUTION
The DISCONNECT position
should be selected only when
the engine is operating in the
normal rpm range to prevent
EDC damage.
c. If spread is indicated after
disconnect, execute the
Emergency Shutdown
procedure, paragraph
15.5.1. If the engine is
allowed to operate due to a
greater emergency, the
EDC should be dumped.
d. Refer to Air‐Conditioning
System Malfunction (In
Flight), paragraph 15.16.

Hint 14

EDC oil temperature excessive. Low oil level in sump. High engine oil temperature.

Note
Low intensity illumination of the EDC TEMP HIGH light is acceptable unless accompanied by a master PRESS SYS light.

Front 15

EDC PRESS LOW light on.

Back 15

a. With loss of spread,
disconnect and dump EDC.
Continue operation.
b. If spread is indicated,
disconnect, monitor for loss
of spread, dump. Continue
operation.
CAUTION
The DISCONNECT position
should be selected only when
the engine is operating in the
normal rpm range to prevent
EDC damage.
c. If spread is indicated after
disconnect, execute the
Emergency Shutdown
procedure, paragraph
15.5.1. If the engine is
allowed to operate due to a
greater emergency, the EDC
should be dumped.
NOTE
If on ground and mission is
continued: Ensure Normal rpm
selected and ground air
conditioning on prior to
disconnect.
d. Refer to Air‐Conditioning
System Malfunction (In
Flight), paragraph 15.16.

Hint 15

EDC oil pressure is low. Low level in sump. EDC drive shaft sheared.

Front 16

REFR OVHT (overheat) light
on.

Back 16

In flight, dump EDC. After light is out,
operation is permitted in the manual
mode at the two‐dot position or
warmer.
On deck, turn off GRD AIR COND
switch; investigate by checking the
HEAT EXCHANGER cbs on BUS B
and BLOWER CONT cb on MEDC. If
cbs are set and the light is out,
operation is permitted in the manual
mode two‐dot position or warmer.

Hint 16

Temperature in cooling duct
exceeds safe limits. On ground:
inoperative heat exchanger blower
fan.

Front 17

L Wing HOT or R Wing HOT
light on.

Back 17

a. Secure wing deicing and
get out of icing area.
b. If light remains on, dump
appropriate EDC.

Hint 17

Air temperature in the wing plenum
area exceeds safe limits. May be
caused by a leak in the bleed air
manifold or EDC plumbing.

Front 18

No. 1, 2, 3, and 4 engine
bleed air valve OPEN lights
on.

Back 18

N/A

Hint 18

When the valve begins to open, the
light will be on. When the valve is
closed, the light should be off.

Front 19

Left and right FUS BLEED
AIR SHUT‐OFF valve OPEN
lights on.

Back 19

N/A

Hint 19

When the valve begins to open, the
light is on. When the valve is closed,
the light should be off.

Front 20

LE HOT light on.

Back 20

Close all bleed air valves. Locate
defective area with temperature
selector. Open all modulating valves.
When necessary, deice the entire wing
using the bleed air valves.

Hint 20

The wing leading edge skin
temperature has increased in
excess of 110 °C. One of the six
modulating valves is either stuck
open or improperly modulating.

Front 21

EMP DE‐ICE light on.

Back 21

Turn switch OFF then ON. If light
remains on, turn switch OFF, increase
airspeed above 200 KIAS; vacate
icing area. If light does not come back
on, a temporary overheat exists.
Continue operation.

Hint 21

Parting strip power relay
deenergized, cycling power relay
deenergized, control relay
deenergized, timer motor failure,
empennage overheat condition.
Open control power circuit breaker.

Front 22

No. 1, 2, 3, or 4 engine
ANTI‐ICING advisory light
on with control switch on.

Back 22

N/A

Hint 22

Fourteenth stage air of sufficient
temperature to melt ice has entered
the torquemeter shroud and the inlet
scoop.

Front 23

No ANTI‐ICING advisory
light with control switch
on.

Back 23

a. Check for horsepower drop.
If normal, continue
operation.
b. If less than normal:
(1) Check for ice buildup on
air inlet scoop. If
excessive, execute the
Emergency Shutdown
procedure, paragraph
15.5.1.
(2) If no ice buildup on air
inlet scoop is observed,
monitor SHP, ***, and
fuel flow. Initial
indications may be a
gradual power loss
followed by erratic
operations. If either of
these indications is
observed, execute the
Emergency Shutdown
procedure, paragraph
15.5.1

Hint 23

One or both areas of system may not
be receiving hot air.

Front 24

ANTI‐ICING advisory light
on and control switch off.

Back 24

On deck, investigate, secure engine,
and return to the line.
In flight, turn on anti‐ice control switch.

a. If a SHP drop is observed,
execute the Emergency
Shutdown procedure,
paragraph 15.5.1.
b. If no SHP drop is observed,
continue engine operation.

Hint 24

a. Abnormal heat in the area.
b. Loss of electrical power to
the solenoid valve.

Front 25

ANTI‐ICING advisory light
remains on after system
utilization.

Back 25

Allow sufficient time for thermal switch
cooling prior to investigating. If no
other abnormal indications exist,
engine operation may be continued for
the remainder of the flight.

Hint 25

Failure of one or both thermal
switches and/or anti‐icing valves.

Front 26

Windshield heat CYCLING
lights on (neon).

Back 26

If unable to start cycling on a cold
windshield, use OVERRIDE switch.

Hint 26

Indicates that electrical power is
being supplied to the windshield
panels. When lights are out,
electrical power is cycled off.

Front 27

Side windshield heat FAIL
light on.

Back 27

Pull side windshield heat power circuit
breaker on main AC bus A.

Hint 27

Windshield power relay and/or
overheat control relay stuck in
energized position when control
switch off.

Front 28

L or R HTR OUT pitot heat
out light on.

Back 28

Check respective circuit breaker and
bus. Monitor equipment for proper
operation.

Hint 28

Indicates electrical current flow to
the pitot heater element has been
interrupted, or current flow detector
is inoperative.

Front 29

No. 1, 2, 3 or 4 feather valve
and NTS lights on.
a. Switch in NTS position.

Back 29

Reset by putting switch to FEATHER
VALVE position and back to NTS
position.

Hint 29

NTS has occurred.

Front 30

No. 1, 2, 3 or 4 feather valve
and NTS lights on.
b. Switch in FEATHER
VALVE position.

Back 30

N/A

Hint 30

Feather valve is being mechanically
positioned to the feather position by
NTS action during an NTS check
(flashing light), or by the emergency
shutdown handle when pulled
(steady light).

Front 31

BOMB BAY COLD light on.

Back 31

Turn bomb bay heat switch ON
(autocycling), open No. 3 or No. 4
engine bleed air valve.

Hint 31

Temperature below desired level in
bomb bay.

Front 32

BOMB BAY HOT light on.

Back 32

Turn BOMB BAY HEAT switch OFF
until light goes out, then heat bomb
bay with switch in OVRD position.
Monitor for proper operation.

Hint 32

Temperature above desired level,
not cycling.

Front 33

DOORS light on.

Back 33

Do not exceed 225 KIAS.

Hint 33

Intake or exhaust door open.
(Should close when APU is shut
down.)

Front 34

ARMED light on.

Back 34

If APU is not being used in flight, turn
arming switch off.

Hint 34

Arming switch on.

Front 35

No. 1, 2, 3, or 4 FILTER light
on.

Back 35

If engine continues to function
normally, continue engine operation.

Hint 35

One or both of the low pressure fuel
filters are restricting flow.

Front 36

No. 1, 2, 3, or 4 PRESS
LOW light on.

Back 36

a. If fuel flow and quantity of
the corresponding engine
are normal and engine
continues to operate
normally, inspect nacelle for
visible fuel. If fuel is visible,
secure engine.
b. In flight, if no fuel visible,
continue operation,
observing engine closely
c. During ground operations, if
no fuel is visible, cycle
respective boost pump or
shift engine to normal rpm
then back to low rpm. If
light goes out and remains
out, continue operation.

Hint 36

Indicates the differential pressure
across the corresponding engine
driven centrifugal boost pump is low.
A flickering light indicates a partial
obstruction of the fuel line.
Note
The FUEL PRESS LOW light should
be out by low rpm.
After start, possible faulty or stuck
pressure switch.

Front 37

No. 1, 2, 3, or 4 TANK
shutoff valve advisory lights
on.

Back 37

Investigate.

Hint 37

Light will illuminate whenever the
corresponding tank valve position
does not coincide with the tank valve
switch. Failure of the valve to open
or close completely energizes the
light.

Front 38

No. 1, 2, 3, or 4 XFEED
valve advisory lights on.

Back 38

Investigate.

Hint 38

Light will illuminate whenever the
corresponding tank valve position
does not coincide with the tank valve
switch. Failure of the valve to open
or close completely energizes the
light.

Front 39

Cross ship X FEED valve
advisory light on.

Back 39

Investigate.

Hint 39

Light will illuminate whenever the
corresponding tank valve position
does not coincide with the tank valve
switch. Failure of the valve to open
or close completely energizes the
light.

Front 40

Tank BOOST pump low
pressure advisory light on.

Back 40

Refer to Fuel Boost Pump Failure,
paragraph 15.8.2.

Hint 40

Light will illuminate whenever the
output pressure of the
corresponding boost pump is low.

Front 41

Transfer pumps PRESS
LOW advisory lights on.

Back 41

Shut off respective pump; refer to
Transfer Pump Failure, Tank 5,
paragraph 15.8.3.

Hint 41

Tank No. 5 is empty or pump output
pressure is low.

Front 42

GEN mechanical failure light
No. 2, 3, or 4 on (steady or
intermittent).

Back 42

Mission should be aborted. If the
generator switch must be left in the
OFF position because of a generator
malfunction, execute the Emergency
Shutdown procedure, paragraph
15.5.1.

Hint 42

Primary generator drive end bearing
has failed.

Front 43

CHIPS light No. 1, 2, 3, or 4
on (steady or intermittent).

Back 43

Check for secondary indications. If
noted, execute Emergency Shutdown
procedure. If no secondary indications
are present, engine operation may be
continued. Refer to Magnetic Chip
Detector Indication, paragraph 15.10.

Hint 43

Metal particles on magnetic plug in
power section or gearbox.

Front 44

OIL HOT light No. 1, 2, 3, or
4 engine on.

Back 44

If power levers in the ground (BETA)
range, open inducers to decrease
temperature. If power levers are in
flight (ALPHA) range, 100 °C for
5 minutes, then 90 °C. Control with oil
cooler flaps position. If unable to
control, secure engine.

Hint 44

Engine oil temperature 100 °C or
over.

Front 45

OIL PRESS light No. 1, 2, 3,
or 4 engine on.

Back 45

Low rpm, light normal. In flight, check
oil pressure gauges; investigate. If oil
pressure is within limits, continue
engine operation. If out of limits,
execute the Emergency Shutdown
procedure.

Hint 45

Either engine oil pressure is below
40 psi or gearbox pressure below
130 psi.

Front 46

PROP PUMP No. 1 light (1,
2, 3, or 4 engine) on.

Back 46

If either or both propeller pump caution
lights illuminate: Continue normal
engine operation and refer to Propeller
Malfunctions, paragraph 15.12.

Hint 46

Reduced flow and drop in pressure
from prop pump 1 due to pump
failure, obstruction, or low oil level.

Front 47

PROP PUMP No. 2 light

Back 47

If either or both propeller pump caution
lights illuminate: Continue normal
engine operation and refer to Propeller
Malfunctions, paragraph 15.12.

Hint 47

Reduced flow and drop in pressure
from prop pump 2 due to pump
failure, obstruction, or low oil level.

Front 48

FUS DUCT HOT light on

Back 48

*1. On ground, secure ground
air‐conditioning and all engine
and APU bleed air, and return
to the line.
*2. In flight, close all engine bleed
and fuselage shutoff valves.
3. If light remains on, dump
EDCs one at a time.
4. If light remains on, land as
soon as possible.

Hint 48

Leak in area around cross ship
manifold, creating excessive
temperature. Can be caused by a
leak in the bleed air manifold, APU
bleed air lines, or EDC plumbing.

Front 49

CABIN PRESS light on.

Back 49

Refer to Pressurization Loss,
paragraph 12.4.

Hint 49

Light on at cabin altitude 10,000
(±500) feet. CABIN PRESS light out
by 8,000 feet on descent.

Front 50

Master DE‐ICING light on.

Back 50

Look for cause in deicing systems on
overhead anti‐icing control panel.
Activate system or secure if
necessary. Reset for continued
warning protection. Get out of icing
area if system is critical and
inoperative.

Hint 50

Alert or fault in deicing system or
bomb bay heating system (L or R
wing hot, LE hot, EMP deice, L or R
pitot heater, or bomb bay hot or
cold).

Front 51

Master ELEC POWER light
on.

Back 51

Locate fault on overhead panel.
Secure faulty system. Reset for
continued warning protection.

Hint 51

Generator No. 2, 3, or 4 OFF light is
on. Overheat of TR No. 1, 2, or 3

Front 52

Master PRESS SYSTEM
light on.

Back 52

Locate fault on overhead panel.
Secure faulty system. Reset for
continued warning protection.

Hint 52

Oil pressure low or oil temperature
high on left or right EDC. Cabin
exhaust fan inoperative.
Refrigeration duct overheat
warning.

Front 53

Master RACK OVHT light
on.

Back 53

Initiate Fire of Unknown Origin
checklist/procedures. Locate
overheated electronic bay(s) by
illuminated individual bay overheat
light(s). Provide required cooling or
secure equipment as necessary.

Hint 53

Electronic rack overheat condition
exists. Also comes on during main
DC bus failure.

Front 54

START VALVE light on.

Back 54

*1. Check overhead panel for
individual engine start control
valve open light.

Hint 54

a. During start sequence
(normal).
b. After start sequence or
during engine operation
(abnormal).
Indicates one of the four engine start
control valves is open.

Front 55

FLAP ASYM light on.

Back 55

a. If accompanied by a
change in flight
characteristics, refer to
split flap Procedures, paragraph
16.6.
b. If not, place flap handle in
position best corresponding
to flap position.
c. Execute split flap Procedures.

Hint 55

Flap asymmetry system has tripped.
If there has been a multiple flap
component failure, the flaps may still
be moving or could be moved by use
of the flap handle.

Front 56

DOOR OPEN light on.

Back 56

Lock the door.

Hint 56

Cabin door (either section), hydraulic
service center door is not locked.

Front 57

RUDDER POWER light on
(flaps up).

Back 57

Actuate rudder pedals to deplete
residual No. 2 hydraulic system
pressure in the rudder boost package.
If the light remains on:
a. Check the rudder boost
shutoff valve circuit
breaker on MEDC.
b. Turn off the No. 2 hydraulic
pump. If the warning light
goes out, the shutoff valve
is inoperative. Turn the No.
2 hydraulic pump on and
make no abrupt rudder
movements.

Hint 57

No. 1 hydraulic system pressure
failure. Shutoff valve has opened.

Front 58

No. 1 or 1A HYD PRESS
light on.

Back 58

Turn off the respective pump;
investigate.
Note
Gear retraction with one
operable hydraulic pump may
result in indication of hydraulic
system failure and unsafe gear
due to heavy system demand.

Hint 58

Respective pump output pressure is below 1,800 psi.

Front 59

No. 2 HYD PRESS light
on.

Back 59

Check No. 2 system pressure. If low,
secure No. 2 pump.

Hint 59

No. 2 pump output pressure is below
1,800 psi.

Front 60

No. 1, 1A, or 2 HYD OIL
HOT light on.

Back 60

Turn off respective pump.

Hint 60

Hydraulic oil temperature is
excessive, restricted coolant flow, not enough fuel in respective inboard fuel tank (minimum 1,000 lb).

Front 61

NTS INOPR.

Back 61

*1. Continue holding out on
feather button. (FE)
*2. Emergency Shutdown handle
— Pull. (FE)
*3. Feather button — Push. (FE)

Hint 61

Inoperative NTS system.

Front 62

ICING light on.

Back 62

Anticipate icing conditions.

Hint 62

Indicates the ice detector probe is
accumulating ice. The frequency of
the light cycling indicates the amount
of ice buildup. Long “off” period
indicates a slow buildup. Light may
illuminate at high angles of attack.

Front 63

Ext pwr available light on

Back 63

light will glow whether or not ext pwr is selected.

Hint 63

indicated elec pwr is connected to the aircraft

Front 64

Leak test accept light

Back 64

maintenance function. refer to appropriate maintenance manuals.

Hint 64

no probable cause.

Front 65

Beta light no 1 2 3 or 4 prop on

Back 65

no corrective action

Hint 65

blade angle is at 10 deg or less

Front 66

Reset advisory light on

Back 66

push reset button to regain control of transfer valves

Hint 66

light will illuminate whenever the refuel cont panel has control of the transfer valves, which are also used to refuel tank nos. 1 2 3 and 4